using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Forms1
{
    public partial class Form2 : Form
    {
        FileStream fileStream;
        Byte[] dataBytes;
        string fileName;

        public Form2()
        {
            InitializeComponent();
        }

        private void SaveButton_Click(object sender, EventArgs e)
        {
            if (richTextBox1.Text.Length > 0)
            {
               fileStream = new FileStream(fileName, FileMode.OpenOrCreate);
               dataBytes = Encoding.ASCII.GetBytes(richTextBox1.Text);
               fileStream.Write(dataBytes, 0, dataBytes.Length);
               fileStream.Close();
            }
        }

        private void OpenButton_Click(object sender, EventArgs e)
        {
            try
            {
                StreamReader streamReader;
                string line;
                OpenFileDialog opf = new OpenFileDialog();
                opf.Title = "select file to open";
                opf.Filter = "TXT document|*.txt";
                if (opf.ShowDialog() == DialogResult.OK)
                {
                    richTextBox1.Text = "";
                    streamReader = new StreamReader(opf.FileName);
                    line = streamReader.ReadToEnd();
                    richTextBox1.Text = line;
                    streamReader.Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("error reading file: " + ex.StackTrace);
            }
        }

        private void AppendButton_Click(object sender, EventArgs e)
        {
            if (richTextBox1.Text.Length > 0)
            {
                SaveFileDialog sfdiag = new SaveFileDialog();
                sfdiag.Title = "Select file destination";
                sfdiag.Filter = "TXT document|* .txt";
                if (sfdiag.ShowDialog() == DialogResult.OK)
                {
                    fileStream = new FileStream(sfdiag.FileName, FileMode.Append);
                    dataBytes = Encoding.ASCII.GetBytes(richTextBox1.Text);
                    fileStream.Write(dataBytes, 0, dataBytes.Length);
                    fileStream.Close();
                }
            }
        }

        private void SplitButton_Click(object sender, EventArgs e)
        {
            string text;
            string[] words;
            string splitSym = Microsoft.VisualBasic.Interaction.InputBox("Split symbol");
            if (richTextBox1.Text.Length > 0)
            {
                text = richTextBox1.Text;
                words = text.Split(splitSym[0]);
                richTextBox1.Text = "";
                foreach (string item in words)
                {
                    richTextBox1.Text += item + Environment.NewLine;
                }
            }
        }

        private void SubstringButton_Click(object sender, EventArgs e)
        {
            string text;
            string nuo = Microsoft.VisualBasic.Interaction.InputBox("nuo");
            string iki = Microsoft.VisualBasic.Interaction.InputBox("iki");
            if (richTextBox1.Text.Length > Convert.ToInt32(iki))
            {
                text = richTextBox1.Text;
                richTextBox1.Text = "";
                richTextBox1.Text = text.Substring(Convert.ToInt32(nuo), Convert.ToInt32(iki));
            }
        }

        private void SearchButton_Click(object sender, EventArgs e)
        {
            string text;
            if (richTextBox1.Text.Length > 0)
            {
                text = richTextBox1.Text;
                string ats = Microsoft.VisualBasic.Interaction.InputBox("Iveskit teksta kurio ieskosite");
                if (text.Contains(ats))
                {
                    int pos = text.IndexOf(ats);
                    richTextBox1.Focus();
                    richTextBox1.Select(pos, ats.Length);
                }
                else
                {
                    MessageBox.Show("Ieškomos frazės nėra");
                }
            }
        }

        private void ReplaceButton_Click(object sender, EventArgs e)
        {
            string rplc, text;
            if (richTextBox1.Text.Length > 0)
            {
                text = richTextBox1.Text;
                string replText = Microsoft.VisualBasic.Interaction.InputBox("Iveskite teksta kuri replace'nsit");
                if (text.Contains(replText))
                {
                    rplc = Microsoft.VisualBasic.Interaction.InputBox("Iveskite nauja teksta");
                    richTextBox1.Text = richTextBox1.Text.Replace(replText, rplc);
                }
                else
                {
                    MessageBox.Show("Nera tokio teksto");
                }
            }
        }

        public void newTextFile(string file)
        {
            file = fileName;
            try
            {
                StreamReader streamReader;
                string line;
                richTextBox1.Text = "";
                streamReader = new StreamReader(fileName);
                line = streamReader.ReadToEnd();
                richTextBox1.Text = line;
                streamReader.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error reading file: " + ex.StackTrace);
            }
        }
    }
}